The research focus is the role of learning in the development of logical reasoning in children between the ages of 7 and 10. The specific goal of this project is to examine the role of learning on logical reasoning strategies. The proposal extends my previous work in three projects: two experiments and one computer-based cognitive model. The two experiments are a microgenetic training study that examines direct instruction on 4th and 5th grade children's strategies of logical reasoning, a cross-sectional study examining errors in evaluating evidence and the relationship between these errors and strategies of logical reasoning. The final project is an ACT-R model of the representation, strategies and error patterns in children's logical reasoning. The overall goal is to develop a production system model to address three limitations in previous theoretical models of logical reasoning: lack of explanation for age-related changes in performance, individual differences in performance, and the role of learning.